JP2008256851A - Electrophotographic photoreceptor and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which has improved cleaning property of a surface of a photosensitive layer without deteriorating excellent electrophotographic characteristics, and which eliminates memory which is an image characteristic (the phenomenon that characters, etc., recorded on an image are printed as residual images), has high sensitivity and high responsiveness and is free from optical fatigue. <P>SOLUTION: The electrophotographic photoreceptor is obtained by forming a photosensitive layer containing at least a charge generating agent, a charge transfer agent and a binder resin on a conductive support, wherein at least a specific polycarbonate copolymer as the binder resin, a specific stilbene compound as the charge transfer agent and an amine-based antioxidant are contained in the photosensitive layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member used for an electrophotographic apparatus such as a copying machine or a laser beam printer, and more particularly to an electrophotographic photosensitive member using an organic photoconductive material.

In general, inorganic materials such as selenium (Se), cadmium sulfide (CdS), zinc oxide (ZnO), and amorphous silicon (a-Si) are used for the photoconductive material of the electrophotographic photosensitive member. A photoreceptor using such an inorganic material is charged with, for example, a charging roller in a dark place, and then image exposure is performed to selectively eliminate the charge of only the exposed portion to form an electrostatic latent image. It is used every time it is visualized and imaged. The basic characteristics required for such an electrophotographic photosensitive member are (1) being able to be charged to an appropriate potential in a dark place, and (2) having a function of being able to eliminate surface charges by light irradiation. The inorganic materials each have advantages and disadvantages. For example, selenium (Se) sufficiently satisfies the characteristics (1) and (2), but is not flexible and difficult to process into a film, and is sensitive to heat and mechanical shock. There are drawbacks such as requiring care in handling. Furthermore, amorphous silicon (a-Si) has the disadvantages that the manufacturing conditions are difficult and the manufacturing cost is high.
Therefore, in recent years, as an electrophotographic photosensitive member, a phthalocyanine or azo compound, which is known as an organic photoconductive substance, is used as a charge generation layer, and a function separation type layered by stacking a charge transfer layer made of a hydrazone compound or the like. Organic photoreceptors are the mainstream.

By the way, bisphenol A type polycarbonate resin has been most commonly used as a binder resin for such an organic photoreceptor.
However, when a photosensitive layer is formed using a bisphenol A type polycarbonate resin as a binder resin, there are disadvantages such as the coating solution for the photosensitive layer being unstable. Therefore, there is a demand for a charge transfer layer material that does not have such a drawback.

Also, since the photosensitive layer using this resin has a large coefficient of friction on the surface, when this electrophotographic photosensitive member is mounted on an electrophotographic apparatus and the electrophotographic process is repeated, it is generally used for cleaning residual toner on the surface of the photosensitive layer. In some cases, the cleaning blade used in the reversal or the generation of abnormal noise has occurred.
Furthermore, since this polycarbonate resin has poor oil resistance, it may accidentally touch the surface of the photosensitive layer during maintenance of the electrophotographic apparatus, etc., and fingerprints may be attached. In many cases, cracks occur and the electrophotographic photosensitive member becomes unusable.

On the other hand, in consideration of the stability of the coating solution, it has also been proposed to use a bisphenol Z-type polycarbonate resin as a material for the photosensitive layer of the electrophotographic photosensitive member. However, even when this bisphenol Z-type polycarbonate resin is used, it has not been able to solve problems such as blade cracking due to a large friction coefficient, generation of abnormal noise and cracks.
Thereafter, an example in which the polycarbonate copolymer of the bisphenol A type and Z type structure and a specific charge transfer agent are combined has been proposed (see, for example, Patent Document 1), but all the above problems such as cleaning properties are solved. We haven't found what we can do yet.
JP-A-5-257297

  The present invention has been made to solve the above-described problems of the prior art, and improves the cleaning property of the surface of the photosensitive layer without impairing the excellent electrophotographic characteristics, and the memory (recording on the image). It is an object of the present invention to provide an electrophotographic photosensitive member that eliminates the phenomenon that printed characters or the like are printed as an afterimage, and has high sensitivity and high response and is free from light fatigue.

  As a result of intensive research to solve the above problems, the present inventors have made use of a polycarbonate copolymer having a specific structure, a charge transfer agent and an additive having a specific structure as a binder resin in the photosensitive layer. It has been found that a photographic photoreceptor is free from the problems of the prior art and maintains excellent electrostatic characteristics over a long period of time, and the present invention has been completed.

〔式中、Ｒ_１とＲ_２は、各々独立に水素原子、ハロゲン原子、炭素数１〜６の置換無置換のアルキル基、炭素数６〜１２の置換無置換のアリール基を表す。Ｒ_３とＲ_４は、各々独立に水素原子、ハロゲン原子、炭素数１〜６の置換無置換のアルキル基、Ｒ_３とＲ_４で形成される炭素数５〜８の１，１−シクロアルキリデン基のいずれかを表し、ｇ及びｉは、各々独立に０〜４の整数を表し、ｈは１〜４の整数を表す。〕
一般式（ＩＩ）

〔Ｒ_５及びＲ_６は、各々独立に水素原子、ハロゲン原子、炭素数１〜６の置換無置換のアルキル基、炭素数６〜１２の置換無置換のアリール基のいずれかを表し、ｊ及びｋは、各々独立に０〜４の整数を表す。〕
一般式（ＩＩＩ）

（式中、Ｒ_７〜Ｒ_９は、各々独立に水素、ハロゲン原子、置換基を有してもよい炭素数１〜６のアルキル基、炭素数６〜１２の置換若しくは無置換のアリール基を表す。） The invention according to claim 1 made on the basis of such a viewpoint is an electrophotographic photosensitive member in which a photosensitive layer having at least a charge generating agent, a charge transfer agent, and a binder resin is formed on a conductive support. A polycarbonate copolymer containing at least a repeating unit represented by the general formula (I) and the general formula (II) as a binder resin, a stilbene compound represented by the general formula (III) as a charge transfer agent, and an amine system An electrophotographic photosensitive member comprising an antioxidant and a triazole ultraviolet absorber.
Formula (I)

[Wherein, R ₁ and R ₂ each independently represents a hydrogen atom, a halogen atom, a substituted unsubstituted alkyl group having 1 to 6 carbon atoms, or a substituted unsubstituted aryl group having 6 to 12 carbon atoms. R ₃ and R ₄ each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, or a 1 to 1-cycloalkylidene having 5 to 8 carbon atoms formed by R ₃ and R _4. Any one of the groups, g and i each independently represents an integer of 0 to 4, and h represents an integer of 1 to 4; ]
Formula (II)

[R ₅ and R ₆ each independently represents a hydrogen atom, a halogen atom, a substituted unsubstituted alkyl group having 1 to 6 carbon atoms, or a substituted unsubstituted aryl group having 6 to 12 carbon atoms, j and k represents the integer of 0-4 each independently. ]
Formula (III)

(In the formula, R _{7 to} R ₉ each independently represent a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. To express.)

  The electrophotographic photosensitive member according to claim 1, further comprising a triazole-based ultraviolet absorber.

The electrophotographic photosensitive member according to claim 1, wherein the charge transfer agent contains a compound represented by the formula (IIIa).
Formula (IIIa)

  The electrophotographic photosensitive member according to claim 1, wherein the amine-based antioxidant is N-phenyl-1-naphthylamine.

  2. The electrophotographic photosensitive member according to claim 1, wherein the benzotriazole ultraviolet absorber is 2- (5-methyl-2-hydroxyphenyl) benzotriazole.

〔式中、Ｒ_１０、Ｒ_１１は、各々独立に水素原子、ハロゲン原子、トリフルオロメチル基、炭素数１〜１２のアルキル基、又は炭素数６〜１２の置換若しくは無置換のアリ−ル基、炭素数１〜１２のアルコキシ基、又は炭素数６〜１２の置換若しくは無置換のアリ−ルオキシ基のいずれかを表し、ａは１〜２００の整数であり、Ｘ_１は、−Ｏ−、又は下記一般式（Ｖ）若しくは（Ｖ’）（式中のＲ_１３は、水素原子、ハロゲン原子、トリフルオロメチル基、炭素数１〜１２のアルキル基、又は炭素数６〜１２の置換若しくは無置換のアリ−ル基、炭素数１〜１２のアルコキシ基、又は炭素数６〜１２の置換若しくは無置換のアリ−ルオキシ基のいずれかを表し、ｂ、ｂ’は、各々独立に０〜６の整数、ｄは０〜４の整数である。）で示される基を表し、Ｘ_２は、−Ｏ−、又は下記一般式（ＶＩ）若しくは（ＶＩ’）（式中、Ｒ_１４は、水素原子、ハロゲン原子、トリフルオロメチル基、炭素数１〜１２のアルキル基、又は炭素数６〜１２の置換若しくは無置換のアリ−ル基、炭素数１〜１２のアルコキシ基、又は炭素数６〜１２の置換若しくは無置換のアリ−ルオキシ基のいずれかを表す。）で示される基を表し、ｆ、ｆ’は、各々独立に０〜６の整数、ｌは０〜４の整数である。〕
一般式（Ｖ）

一般式（Ｖ’）

一般式（ＶＩ）

一般式（ＶＩ’）

The electrophotographic photoreceptor according to claim 1, further comprising: a polycarbonate copolymer containing a repeating unit represented by the general formula (I), the general formula (II), and the general formula (IV) as a binder resin in the photosensitive layer. An electrophotographic photosensitive member characterized by containing.
Formula (IV)

[Wherein R _{10 and} R ₁₁ are each independently a hydrogen atom, a halogen atom, a trifluoromethyl group, an alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. , An alkoxy group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 12 carbon atoms, a is an integer of 1 to 200, and X ₁ is —O—, Or the following general formula (V) or (V ′) (wherein R ₁₃ represents a hydrogen atom, a halogen atom, a trifluoromethyl group, an alkyl group having 1 to 12 carbon atoms, or a substituted or non-substituted group having 6 to 12 carbon atoms) It represents either a substituted aryl group, an alkoxy group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 12 carbon atoms, and b and b ′ are each independently 0 to 6 And d is an integer of 0 to 4.) X ₂ represents —O—, or the following general formula (VI) or (VI ′) (wherein R ₁₄ represents a hydrogen atom, a halogen atom, a trifluoromethyl group, an alkyl having 1 to 12 carbon atoms). Or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 12 carbon atoms. ), F and f ′ are each independently an integer of 0 to 6, and l is an integer of 0 to 4. ]
General formula (V)

General formula (V ')

Formula (VI)

Formula (VI ')

〔式中、Ｒ_２１〜Ｒ_３２は、各々独立に炭素数１〜６のアルキル基又は炭素数６〜１２の芳香族炭化水素基のいずれかを表し、ｍ〜ｐは、各々独立に２〜６の整数を表し、ｑは０〜２００の整数を表す。〕 The electrophotographic photoreceptor according to claim 1, further comprising a polycarbonate copolymer containing a repeating unit represented by the general formula (I), the general formula (II), and the general formula (VII) as a binder resin in the photosensitive layer. An electrophotographic photosensitive member characterized by comprising:
Formula (VII)

[Wherein, R _{21 to} R ₃₂ each independently represents an alkyl group having 1 to 6 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and m to p are each independently 2 to 2. The integer of 6 is represented, q represents the integer of 0-200. ]

  2. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer comprises a charge generation layer containing a charge generation agent and a charge transfer layer containing at least a charge transfer agent thereon. It is a photoreceptor.

  2. The electrophotographic photosensitive member according to claim 1, wherein the ratio of the binder resin to the charge transfer agent is 1.25 to 2.5 (weight ratio).

  The electrophotographic photosensitive member according to claim 1, wherein the charge generating agent is Y-type oxytitanium phthalocyanine.

  The electrophotographic apparatus according to any one of 1 to 10, further comprising a photosensitive member and a charging member to which a voltage is applied so as to be in contact with the photosensitive member.

  As can be seen from the characteristic differences between Examples and Comparative Examples described later, the electrophotographic photosensitive member of the present invention has repetitive stability and can meet high market demands.

  A preferred embodiment of an electrophotographic photoreceptor according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a structural example of the electrophotographic photosensitive member of the present invention. A function in which a charge generation layer (2) containing at least a charge generation agent is formed on a conductive support (1), and a charge transfer layer (3) containing at least a charge transfer agent is formed thereon. A separation type electrophotographic photosensitive member is applied. In this case, the photosensitive layer (4) is formed by the charge generation layer and the charge transfer layer.

  Various methods can be used as the method for forming the charge generation layer. For example, an oxytitanium phthalocyanine pigment is used as a charge generation agent, and a coating solution dispersed or dissolved in a suitable solvent together with a binder resin is used as a predetermined base. It can apply | coat on the support body used, and can be formed by making it dry as needed.

  The charge transfer layer has at least the charge transfer agent of the present invention, which will be described later, and this charge transfer layer is formed by, for example, binding the charge transfer agent on the charge generation layer as a base using a binder resin. Can be formed.

  Various methods can be used as a method for forming the charge transfer layer. In general, a coating solution in which a charge transfer agent is dispersed or dissolved in a suitable solvent together with a binder resin is applied to the underlying charge generation layer. The method of apply | coating to and drying can be used.

  Further, the present invention can also be applied to an inversely laminated electrophotographic photosensitive member in which a charge generation layer and a charge transfer layer are laminated upside down. Furthermore, the present invention can also be applied to a single layer type electrophotographic photosensitive member containing a charge generating agent and a charge transfer agent in the same layer. If necessary, an intermediate layer may be provided between the conductive support and the charge generation layer, or a protective layer may be provided on the photosensitive layer.

  Examples of the conductive support that can be used in the present invention include aluminum, brass, stainless steel, nickel, chromium, titanium, gold, silver, copper, tin, platinum, molybdenum, indium, and other simple metals and alloys thereof. The body is mentioned. The shape may be any shape as long as it is flexible, such as a sheet shape, a film shape, and a belt shape, and may be endless or endless. The diameter of the conductive support is particularly effective when it is 60 mm or less, preferably 30 mm or less.

  Among these, aluminum alloys such as JIS 3000, JIS 5000, and JIS 6000 are used, and general methods such as EI (Extension Ironing) method, ED (Extension Drawing) method, DI (Drawing Ironing) method, II (Impact Ironing) method, etc. A conductive support formed by the method is preferable, and the surface of the conductive support is further subjected to surface treatment such as diamond cutting or polishing, surface treatment such as polishing, anodizing treatment, or the like. Anything such as a non-cutting tube may be used.

  Moreover, when using resin as a base | substrate, conductive agents, such as metal powder and conductive carbon, can be contained in resin, and conductive resin can also be used as base | substrate formation resin.

  Further, when glass is used for the substrate, the surface thereof may be coated with tin oxide, indium oxide, or aluminum iodide so as to have conductivity.

  Further, an intermediate layer may be formed on the support. This intermediate layer has an adhesion improving function, a barrier function for preventing an inflow current from the aluminum tube, a defect covering function on the surface of the aluminum tube, and the like. Various resins such as polyethylene resin, acrylic resin, epoxy resin, polycarbonate resin, polyurethane resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, polyamide resin, nylon resin, alkyd resin, and melamine resin are used for this intermediate layer. be able to. These resin layers may be composed of a single resin or a mixture of two or more resins. Moreover, a metal compound, carbon, silica, resin powder, etc. can be dispersed in the layer. Furthermore, various pigments, electron accepting substances, electron donating substances, and the like can be contained for improving the characteristics.

  These intermediate layers can be formed using an appropriate solvent, dispersion, and coating method in the same manner as the photosensitive layer. The film thickness of the intermediate layer is 0.1 μm to 50 μm, preferably 0.5 μm to 20 μm.

  As the charge generating agent that can be used in the present invention, oxytitanium phthalocyanine is desirable since it has high sensitivity characteristics. Among them, Y-type oxytitanium phthalocyanine in the X-ray diffraction peak diagram shown in FIG. 3 is the charge transfer agent of the present invention. Good compatibility in combination. Furthermore, the present invention is not limited thereto. Others such as selenium, selenium-tellurium, selenium-arsenic, amorphous silicon, metal-free phthalocyanine, other metal phthalocyanine pigments, monoazo pigments, disazo pigments, trisazo pigments, polyazo pigments, indigo pigments, selenium pigments, toluidine pigments, pyrazoline pigments Perylene pigments, quinacridone pigments, polycyclic quinone pigments, pyrylium salts, and the like can be used.

  These charge generating agents may be used alone or in combination of two or more in order to obtain an appropriate photosensitivity wavelength and sensitizing action. The film thickness of the charge generation layer is 0.01 to 5 μm, preferably 0.1 to 2 μm.

  Next, as the binder resin used in the photosensitive layer of the present invention, general formula (I), general formula (II), general formula (IV), general formula (V), general formula (VI), general formula (VII) Specific examples of) are shown below, but are not limited thereto.

式（Ｉｂ）

式（Ｉｃ）

式（Ｉｄ）

式（Ｉｅ）

式（Ｉｆ）

式（Ｉｇ）

式（Ｉｈ）

Specific examples of general formula (I) are shown below.
Formula (Ia)

Formula (Ib)

Formula (Ic)

Formula (Id)

Formula (Ie)

Formula (If)

Formula (Ig)

Formula (Ih)

式（ＩＩｂ）

式（ＩＩｃ）

Specific examples of the general formula (II) are shown below.
Formula (IIa)

Formula (IIb)

Formula (IIc)

式（ＩＶｂ）

式（ＩＶｃ）

式（ＩＶｄ）

Specific examples of general formula (IV) are shown below.
Formula (IVa)

Formula (IVb)

Formula (IVc)

Formula (IVd)

Specific examples of the general formula [VII] are shown below.
Formula [VIIa]

  On the other hand, in the electrophotographic photoreceptor of the present invention, a binder resin other than the specific polycarbonate copolymer described above can be contained in the photosensitive layer.

  Examples of binder resins that can be used to form the photosensitive layer include polycarbonate resins, styrene resins, acrylic resins, styrene-acrylic resins, ethylene-vinyl acetate resins, polypropylene resins, vinyl chloride resins, chlorinated polyethers, and chlorides. Vinyl-vinyl acetate resin, polyester resin, furan resin, nitrile resin, alkyd resin, polyacetal resin, polymethylpentene resin, polyamide resin, polyurethane resin, epoxy resin, polyarylate resin, diarylate resin, polysulfone resin, polyethersulfone resin, Polyallyl sulfone resin, silicone resin, ketone resin, polyvinyl butyral resin, polyether resin, phenol resin, EVA (ethylene / vinyl acetate / copolymer) resin, ACS (acrylonitrile / chlorinated) Riechiren styrene) resin, ABS (acrylonitrile butadiene styrene) resins, photocurable resins such as epoxy arylate. These may be used alone or in combination of two or more. In addition, it is more preferable to use a mixture of resins having different molecular weights because the hardness and wear resistance can be improved.

  In the case where the photosensitive layer comprises a charge generation layer and a charge transfer layer, the resin can be applied to either layer.

  The amount of the binder resin is 10 to 500 parts by weight, preferably 25 to 300 parts by weight with respect to 100 parts by weight of the charge generating agent.

〔式中、Ｒ_１〜Ｒ_３は、各々独立に水素、ハロゲン原子、置換基を有してもよい炭素数１〜６のアルキル基、炭素数６〜１２の置換若しくは無置換のアリ−ル基を表す。〕 Next, the electrophotographic photoreceptor of the present invention contains a compound represented by the general formula (III) as a charge transfer agent.
Formula (III)

[Wherein R _{1 to} R ₃ each independently represents hydrogen, a halogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl having 6 to 12 carbon atoms. Represents a group. ]

  The above charge transfer agent has good compatibility with the binder resin of the present invention and can provide an electrophotographic photosensitive member having high environmental resistance.

式（ＩＩＩｂ）

式（ＩＩＩｃ）

式（ＩＩＩｄ）

Of the compounds represented by the general formula (III), the compounds represented by the formulas (IIIa) to (IIId) are particularly preferable because of their good compatibility with the binder resin of the present invention.
Specific compounds will be shown below, but are not limited thereto.
Formula (IIIa)

Formula (IIIb)

Formula (IIIc)

Formula (IIId)

  In the present invention, the ratio of the binder resin to the charge transfer agent is preferably in the range of 1.25 to 2.5 (weight ratio). More preferably, it is 1.5 to 2.0 (weight ratio). If it is more than 2.5 (weight ratio), the electrical characteristics deteriorate, for example, the residual potential increases. On the other hand, when it is less than 1.25 (weight ratio), mechanical properties such as wear resistance are deteriorated.

  Furthermore, the compound represented by the general formula (III) and other charge transfer agents can be mixed and used. In this case, the content ratio of the compound of the general formula (III) and the other compound is in the range of (III): other compound = 50: 50 to 5:95, preferably 30:70 to 5:95.

  Other charge transfer agents include polyvinyl carbazole, halogenated polyvinyl carbazole, polyvinyl pyrene, polyvinyl indoloquinoxaline, polyvinyl benzothiophene, polyvinyl anthracene, polyvinyl acridine, polyvinyl pyrazoline, polyacetylene, polythiophene, polypyrrole, polyphenylene, polyphenylene vinylene, poly Conductive polymer compounds such as isothianaphthene, polyaniline, polydiacetylene, polyheptadiene, polypyridinediyl, polyquinoline, polyphenylene sulfide, polyferrocenylene, polyperinaphthylene, and polyphthalocyanine can be used. Further, as a low molecular compound, trinitrofluorenone, tetracyanoethylene, tetracyanoquinodimethane, quinone, diphenoquinone, naphthoquinone, anthraquinone and derivatives thereof, polycyclic aromatic compounds such as anthracene, pyrene, phenanthrene, indole, carbazole, Nitrogen-containing heterocyclic compounds such as imidazole, fluorenone, fluorene, oxadiazole, oxazole, pyrazoline, hydrazone, triphenylmethane, triphenylamine, enamine, stilbene and the like can be used. Further, a polymer solid electrolyte in which a polymer compound such as polyethylene oxide, polypropylene oxide, polyacrylonitrile, polymethacrylic acid or the like is doped with a metal ion such as Li ion can also be used. Furthermore, an organic charge transfer complex formed of an electron donating compound typified by tetrathiafulvalene-tetracyanoquinodimethane and an electron accepting compound, etc. can be used. Desired photoreceptor characteristics can be obtained by mixing and adding the above compounds.

  As a coating method of the coating solution, methods such as dip coating, spray coating, ring coating, bar coating spinner coating and the like can be used.

  Solvents used in the coating solution include alcohols such as methanol, ethanol, n-propanol, i-propanol and butanol, saturated aliphatic hydrocarbons such as pentane, hexane, heptane, octane, cyclohexane and cycloheptane, toluene and xylene. Aromatic hydrocarbons such as dichloromethane, chlorinated hydrocarbons such as dichloromethane, dichloroethane, chloroform, chlorobenzene, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran (THF), methoxyethanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone , Esters such as ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, diethyl ether, dimethoxyethane, tetrahydride Furan, dioxolane, dioxane or ether solvents such as anisole,, N, N-dimethylformamide, there are dimethyl sulfoxide and the like. Among these, ketone solvents, ester solvents, ether solvents, or halogenated hydrocarbon solvents are preferable, and these can be used alone or as a mixed solvent of two or more.

  Antioxidants, ultraviolet absorbers, radical scavengers, softeners, curing agents, crosslinking agents, and the like are added to the coating solution for producing the electrophotographic photoreceptor of the present invention, so that the characteristics and durability of the photoreceptor are increased. The mechanical characteristics can be improved. In particular, the combined use of an antioxidant and an ultraviolet absorber contributes to improving the durability of the photoreceptor and is useful. Among them, amine-based antioxidants are preferable for the photosensitive layer, and examples thereof include N-phenyl-1-naphthylamine, N-phenyl-N′-isopropyl-p-phenylenediamine, N, N-diethyl-p-phenylenediamine, N -Phenyl-N'-ethyl-2-methyl-p-phenylenediamine, N-ethyl-N-hydroxyethyl-p-phenylenediamine, alkylated diphenylamine, N, N'-diphenyl-p-phenylenediamine, N, N '-Diallyl-p-phenylenediamine, N-phenyl-1,3-dimethylbutyl-p-phenylenediamine, 4,4'-dioctyl-diphenylamine, 4,4'-dioctyl-diphenylamine, 6-ethoxy-2,2 , 4-Trimethyl-1,2-dihydroquinoline, 2,2,4-trimethyl-1, - it can be exemplified dihydroquinoline, N- phenyl -β- naphthylamine, N, a N'- di-2-naphthyl -p- phenylenediamine.

  Phenol antioxidants include 2,6-di-tert-butylphenol, 2,6-di-tert-4-methoxyphenol, 2-tert-butyl-4-methoxyphenol, 2,4-dimethyl-6-tert. -Butylphenol, 2,6-di-tert-butyl-4-methylphenol, butylated hydroxyanisole, stearyl-propionate-β- (3,5-di-tert-butyl-4-hydroxyphenyl), α-tocopherol, monophenols such as β-tocopherol, n-octadecyl-3- (3′-5′-di-tert-butyl-4′-hydroxyphenyl) propionate, 2,2′-methylenebis (6-tert-butyl-4) -Methylphenol), 4,4'-butylidene-bis- (3-methyl-6-tert-butyl) Enol), 4,4′-thiobis (6-tert-butyl-3-methylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3 , 5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3 (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate] Polyphenols such as methane are preferred, and one or more of them can be simultaneously contained in the photosensitive layer.

  Ultraviolet absorbers include 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3,5-di-tert-butyl-2-hydroxyphenyl) benzotriazole, 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5 -Di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-tert-amyl-2-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-5 ' -Tert-octylphenyl) benzotriazoles such as benzotriazole, phenyl salicylate, salicylic acid-p-te Salicylic acid series such as rt-butylphenyl and salicylic acid-p-octylphenyl are preferred, and benzotriazole ultraviolet absorbers are particularly preferred. One or more of the above antioxidants can be simultaneously contained in the photosensitive layer.

  The amount of the amine-based antioxidant added to the electrophotographic photoreceptor of the present invention is preferably in the range of 3 to 20% by weight with respect to the binder resin. On the other hand, the addition amount of the ultraviolet absorber is preferably 3 to 30% by weight with respect to the binder resin.

In addition, a thin film made of an organic thin film such as polyvinyl formal resin, polycarbonate resin, fluororesin, polyurethane resin, or silicone resin, or a siloxane structure formed from a hydrolyzate of a silane coupling agent is formed on the photosensitive layer. A surface protective layer may be provided as a film. In that case, the durability of the photoreceptor is improved, which is preferable. This surface protective layer may be provided in order to improve functions other than the durability improvement.
The thickness of the protective layer is suitably from 0.1 to 20 μm.

  The electrophotographic apparatus on which the electrophotographic photosensitive member of the present invention is mounted has at least commonly used methods such as at least charging, exposure, and transfer processes. Specifically, the charging method may be any of a contact type such as a brush or a roller, or a non-contact type such as a scorotron or a corotron, and may be a positive or negative charged charge. The exposure method may be either LED or LD. The development method may be two-component, one-component, or magnetic / non-magnetic. The transfer method may be either a roller or a belt. As the cleaning method, blade cleaning, brush cleaning, a charging unit or a developing unit may be used as a cleaning process. Further, a method in which the cleaning process and the charge removal process are omitted may be used.

  Next, the electrophotographic apparatus of the present invention will be described. FIG. 2 is a schematic configuration diagram of the electrophotographic apparatus of the present invention. A photoconductor 11 is provided with a charging member 12 in contact therewith. A voltage is supplied from the power source 13 to the charging member in a contact type. Around the photosensitive member, an exposure device 14, a developing device 15, a transfer device 16, a cleaning device 17, and static eliminating devices 18 and 19 are fixing devices.

  Hereinafter, examples of the electrophotographic photosensitive member according to the present invention will be described in detail together with experimental examples and comparative examples.

  Alkyd resin (Beckolite M-6401-50 manufactured by Dainippon Ink and Chemicals) and amino resin (Super Becamine G-821-60 manufactured by Dainippon Ink and Chemicals, Inc.) on a cylindrical drum made of uncut aluminum with a diameter of 30 mm. ) Is mixed at a ratio of 65:35, and the mixed resin and titanium oxide (CR-EL Ishihara Sangyo Co., Ltd.) are mixed at a ratio of 1: 3, and dissolved in methyl ethyl ketone as a coating solution to give a film thickness of 1.5 μm. Formed with.

  Next, 10 g of oxytitanium phthalocyanine powder having a maximum peak at an X-ray diffraction angle Cukα (2θ ± 0.2 degrees) of 27.3 degrees in FIG. 3 was added to 500 ml of glass beads and 1,3 dioxolane with a polyvinyl butyral resin (BX- A solution in which 10 g of 1 Sekisui Chemical Co., Ltd. was dissolved was added and dispersed for 20 hours with a sand mill disperser. The resulting dispersion was filtered to remove the glass beads, thereby preparing a coating solution for a charge generation layer. This was dip-coated on the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm.

  Next, a polycarbonate copolymer having a viscosity average molecular weight (Mv: 40,000) at a molar ratio (mol%) of 87.50: 12.50 as a binder resin and a formula (Ia) and a formula (IIa), and charge transfer As the agent, a compound represented by the formula (IIIa), N-phenyl-1-naphthylamine as an aromatic amine-based antioxidant, and 2- (5-methyl-2-hydroxyphenyl) benzotriazole as an ultraviolet absorber. Were prepared in a weight ratio of 1.67: 1.0: 0.05: 0.05 and dissolved in tetrahydrofuran to prepare a charge transfer layer coating solution. The substrate on which the charge generation layer was formed was dip-coated in the charge transfer layer coating solution and dried at 130 ° C. for 60 minutes to form a charge transfer layer having a thickness of 25.0 μm, thereby producing an electrophotographic photosensitive member.

  The polycarbonate copolymer used in Example 1 is represented by the formula (Ib) and the formula (IIa), except that the charge transfer layer represented by the formula (IIIb) is replaced with a film thickness of 28 μm. Produced an electrophotographic photosensitive member in the same manner as in Example 1.

  An electrophotographic process was carried out in the same manner as in Example 1 except that the polycarbonate copolymer used in Example 1 was replaced by the charge transfer agent represented by Formula (Ic) and Formula (IIa) and represented by Formula (IIIc). A photoconductor was prepared.

  The polycarbonate copolymer used in Example 1 is replaced with the charge transfer agent represented by the formula (Id) and the formula (IIa), and instead of the charge transfer agent represented by the formula (IIId), the binder resin for the charge transfer agent. The electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the ratio of 1.25 was changed to 1.25 weight ratio.

  An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that instead of the Y-type oxytitanium phthalocyanine pigment used in Example 1, the α-type oxytitanium phthalocyanine pigment shown in FIG. 4 was used.

  An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the β-type oxytitanium phthalocyanine pigment shown in FIG. 5 was used instead of the Y-type oxytitanium phthalocyanine pigment used in Example 1.

  An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the ratio of the binder resin to the charge transfer agent used in Example 1 was changed to 2.50 weight ratio.

  The electrophotographic photosensitive member was the same as in Example 1 except that the ratio of the binder resin to the charge transfer agent used in Example 1 was changed to 1.0% by weight and the film thickness of the charge transfer layer was 18 μm. It was created.

  The polycarbonate copolymer used in Example 1 has the formula (Ia), the formula (IIa), the formula (IVa), the molar ratio (mol%) of 85.0: 14.9: 0.1, and the viscosity. An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the polycarbonate copolymer having an average molecular weight (Mv: 40,000) was used.

  An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the ultraviolet absorber 2- (5-methyl-2-hydroxyphenyl) benzotriazole used in Example 1 was omitted.

(Comparative Example 1)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transfer agent represented by the formula (B) was used instead of the charge transfer agent used in Example 1.
Formula (B)

(Comparative Example 2)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the charge transfer agent represented by the formula (C) was used instead of the charge transfer agent used in Example 1.
Formula (C)

(Comparative Example 3)
In place of the polycarbonate copolymer used in Example 1, a polycarbonate resin having only the formula (Ih) viscosity average molecular weight (Mv: 50,000) was used, and the electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that. Created.

(Comparative Example 4)
Instead of the polycarbonate copolymer used in Example 1, a polycarbonate copolymer of formula (Ia) and formula (Ig) having a molar ratio of 0.5: 0.5 and a viscosity average molecular weight (Mv: 50,000) was used. Otherwise, an electrophotographic photosensitive member was prepared in the same manner as in Example 1.

(Comparative Example 5)
Example 1 except that only the phenolic antioxidant 2,6-di-tert-butyl-4-methylphenol was used in place of the aromatic amine-based antioxidant and ultraviolet absorber used in Example 1. An electrophotographic photoreceptor was prepared in the same manner as described above.

(Comparative Example 6)
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the aromatic amine antioxidant N-phenyl-1-naphthylamine used in Example 1 was omitted.

Photoconductor evaluation <Evaluation of electrical characteristics with a simple measuring instrument>
A photosensitive drum evaluation device (dynamic mode measurement) was used for the function-separated type photoreceptors produced in Examples 1 to 10 and Comparative Examples 1 to 6, and the electrophotographic characteristics were evaluated under the following conditions.

Using an electrophotographic photosensitive member evaluation apparatus (manufactured by Yamanashi Electronics Co., Ltd.), the electrophotographic photosensitive members produced in the examples and comparative examples are divided into three environments (temperature 10 ° C / humidity 10%, temperature 23 ° C / humidity 50%, temperature (35 ° C / 80% humidity) under the scorotron method, the discharge current is adjusted so that the surface potential of the photoconductor becomes -700 V, the electrophotographic photoconductor is charged, and exposure is performed when irradiated with a semiconductor laser having a wavelength of 780 nm. The surface potential of the photosensitive member was attenuated and adjusted to 1/2 (-350 V) with the amount of energy. The residual exposure potential was set to the photoreceptor residual potential (VL) with an exposure energy amount of 1.0 μJ / cm ² . For neutralization, an LED (20 μW) having a wavelength of 660 nm was used. The drum speed of the electrophotographic photosensitive member was 150 rpm, and the time from the laser light irradiation to the measurement of the potential (movement time from the exposure position to the measurement position = peripheral speed) was 0.06 seconds. The results are shown in Table 1. The numerical value is an average value of three environmental measurement results.

<Sensitivity evaluation>
E1 / 2 (μJ / cm ² ): exposure energy value when the surface potential is attenuated to −350 V, which is ½

<Response evaluation>
Potential at the time of exposure of 0.4 μJ / cm ² (absolute potential when the peripheral speed of the photosensitive member is swung from 0.06 to 0.10 sec)

感光体の表面電位が−７００Ｖになるように放電電流を調節し、電子写真感光体を帯電させ、光暴露後１時間放置した時の表面電位

Discharge current is adjusted so that the surface potential of the photoconductor becomes −700 V, the electrophotographic photoconductor is charged, and the surface potential is left for 1 hour after exposure to light.

<Evaluation of actual image>
The electrophotographic photoreceptors produced in Examples 1 to 10 and Comparative Examples 1 to 6 were mounted on a Ricoh CX3000 and image evaluation was performed.

<Light exposure characteristics>
After the irradiation light white fluorescent lamp 1000 lux and the irradiation time were shaken at 5 minutes, 10 minutes, 30 minutes and 60 minutes, the density change in the halftone image was visually evaluated. ○ indicates no change in concentration, and Δ indicates a change in concentration.

<Memory>
The presence or absence of an afterimage on the image after printing 4000 sheets was visually evaluated in a room temperature environment at a temperature of 23 ° C. and a humidity of 50%. In the five-step evaluation, rank 5 was given when no afterimage was seen, rank 3 was given a thin afterimage, and rank 1 was clearly seen.

<Cleanability>
The presence or absence of toner contamination on the surface of the photoreceptor after 4000 sheets printing (one-sheet intermittent mode) and the presence or absence of toner contamination on the charging roller were visually observed. The case where both were not dirty was indicated by ◯, the case where there was a partial contamination was indicated by Δ, and the case where the contamination was entirely present was indicated by X.

  As is apparent from Table 1, Examples 1 to 10 are examples of photosensitivity using a simple measuring instrument as an environmental dependency evaluation by combining the binder resin of the present invention with a charge transfer agent, an antioxidant and an ultraviolet absorber. In the evaluation of body electrical characteristics, E1 / 2 = sensitivity potential and responsiveness were both good. In the evaluation of image characteristics with an actual printer, there were no significant changes in the evaluation of light exposure characteristics, chargeability after light exposure, memory, and cleaning properties, and the characteristics of the photoconductor were good. In Examples 5 and 6, the charge generating agent is changed, but it can be used in an electrophotographic apparatus having a slightly lower sensitivity but a different sensitivity range. In Example 7, when the ratio of the charge transfer agent is large with respect to the resin, the response is slightly deteriorated. In Example 8, when the ratio of the charge transfer agent to the resin is small, mechanical properties such as wear resistance are deteriorated, and the memory and cleaning properties are deteriorated.

  Further, if the charge transfer layer is thin, the sensitivity is lowered, but both are in the usable range. In Example 9, when the thickness of the charge transfer layer is large, the response is slightly deteriorated, but it is at a sufficiently usable level. Example 10 can be used to the extent that the charging potential after light fatigue drops slightly when it does not contain an ultraviolet absorber.

  On the other hand, Comparative Examples 1 and 2 had low sensitivity potential and responsiveness due to combinations with other charge transfer agents, and were not satisfactory as photoreceptor characteristics. Further, in Comparative Examples 3 and 4, when the combination of the other binder resin and the charge transfer agent of the present invention was used, the cleaning property was poor, and the photoreceptor characteristics were not satisfactory. Further, Comparative Example 5 had poor light exposure characteristics when other antioxidants were applied. In Comparative Example 6, when the antioxidant of the present invention was not contained, the light exposure characteristics and the memory characteristics were poor.

FIG. 2 shows a cross-sectional view of the electrophotographic photosensitive member of the present invention. 1 is a schematic configuration diagram of an electrophotographic apparatus of the present invention. The X-ray diffraction peak figure of Y type oxytitanium phthalocyanine is shown. An X-ray diffraction peak diagram of α-type oxytitanium phthalocyanine is shown. An X-ray diffraction peak diagram of β-type oxytitanium phthalocyanine is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Charge generation layer 3 Charge transfer layer 4 Photosensitive layer 11 Photoconductor 12 Charging member 13 Power supply 14 Exposure apparatus 15 Development apparatus 16 Transfer apparatus 17 Cleaning apparatus 18 Static elimination apparatus 19 Fixing apparatus

Claims (11)

In an electrophotographic photosensitive member in which a photosensitive layer having at least a charge generating agent, a charge transfer agent, and a binder resin is formed on a conductive support, at least the general formula (I) and the general formula ( II) An electrophotographic photoreceptor comprising a polycarbonate copolymer containing a repeating unit represented by formula (II), a stilbene compound represented by formula (III) as a charge transfer agent, and an amine-based antioxidant. .
Formula (I)

[Wherein, R ₁ and R ₂ each independently represents a hydrogen atom, a halogen atom, a substituted unsubstituted alkyl group having 1 to 6 carbon atoms, or a substituted unsubstituted aryl group having 6 to 12 carbon atoms. R ₃ and R ₄ each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, or a 1 to 1-cycloalkylidene having 5 to 8 carbon atoms formed by R ₃ and R _4. Any one of the groups, g and i each independently represents an integer of 0 to 4, and h represents an integer of 1 to 4; ]
Formula (II)

[R ₅ and R ₆ each independently represents a hydrogen atom, a halogen atom, a substituted unsubstituted alkyl group having 1 to 6 carbon atoms, or a substituted unsubstituted aryl group having 6 to 12 carbon atoms, j and k represents the integer of 0-4 each independently. ]
Formula (III)

(In the formula, R _{7 to} R ₉ each independently represent a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. To express.)   2. The electrophotographic photosensitive member according to claim 1, further comprising a triazole ultraviolet absorber. 2. The electrophotographic photosensitive member according to claim 1, wherein the charge transfer agent contains a compound represented by the formula (IIIa).
Formula (IIIa)

  2. The electrophotographic photosensitive member according to claim 1, wherein the amine-based antioxidant is N-phenyl-1-naphthylamine.   2. The electrophotographic photosensitive member according to claim 1, wherein the benzotriazole ultraviolet absorber is 2- (5-methyl-2-hydroxyphenyl) benzotriazole. 2. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer contains a polycarbonate copolymer containing a repeating unit represented by general formula (I), general formula (II) and general formula (IV) as a binder resin. An electrophotographic photosensitive member characterized by comprising:
Formula (IV)

[Wherein R _{10 and} R ₁₁ are each independently a hydrogen atom, a halogen atom, a trifluoromethyl group, an alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. , An alkoxy group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 12 carbon atoms, a is an integer of 1 to 200, and X ₁ is —O—, Or the following general formula (V) or (V ′) (wherein R ₁₃ represents a hydrogen atom, a halogen atom, a trifluoromethyl group, an alkyl group having 1 to 12 carbon atoms, or a substituted or non-substituted group having 6 to 12 carbon atoms) It represents either a substituted aryl group, an alkoxy group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 12 carbon atoms, and b and b ′ are each independently 0 to 6 And d is an integer of 0 to 4.) X ₂ represents —O—, or the following general formula (VI) or (VI ′) (wherein R ₁₄ represents a hydrogen atom, a halogen atom, a trifluoromethyl group, an alkyl having 1 to 12 carbon atoms). Or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 12 carbon atoms. ), F and f ′ each independently represent an integer of 0 to 6, and l represents an integer of 0 to 4. ]
General formula (V)

General formula (V ')

Formula (VI)

Formula (VI ')

2. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains a polycarbonate copolymer containing a repeating unit represented by the general formula (I), the general formula (II), and the general formula (VII) as a binder resin. An electrophotographic photosensitive member characterized by comprising:
Formula (VII)

[Wherein, R _{21 to} R ₃₂ each independently represents an alkyl group having 1 to 6 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and m to p are each independently 2 to 2. The integer of 6 is represented, q represents the integer of 0-200. ]   2. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer comprises a charge generation layer containing a charge generation agent and a charge transfer layer containing at least a charge transfer agent thereon. body.   2. The electrophotographic photosensitive member according to claim 1, wherein the ratio of the binder resin to the charge transfer agent is 1.25 to 2.5 (weight ratio).   2. The electrophotographic photosensitive member according to claim 1, wherein the charge generating agent is Y-type oxytitanium phthalocyanine.   The electrophotographic apparatus containing the photosensitive member according to any one of the above items 1 to 10, further comprising a photosensitive member and a charging member to which a voltage is applied so as to be in contact with the photosensitive member.

Images